WASHINGTON: NASA has announced two robotic missions to asteroids that will open new windows on one of the earliest eras in the history of our solar system – a time less than 10 million years after the birth of the Sun.
The missions, known as Lucy and Psyche, were chosen from five finalists and will proceed to mission formulation, with the goal of launching in 2021 and 2023, respectively.
"Lucy will visit a target-rich environment of Jupiter's mysterious Trojan asteroids, while Psyche will study a unique metal asteroid that's never been visited before," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate in Washington.
Lucy, a robotic spacecraft, is scheduled to launch in October 2021. It is slated to arrive at its first destination, a main belt asteroid, in 2025.
From 2027 to 2033, Lucy will explore six Jupiter Trojan asteroids. These asteroids are trapped by Jupiter's gravity in two swarms that share the planet's orbit, one leading and one trailing Jupiter in its 12-year circuit around the Sun.
The Trojans are thought to be relics of a much earlier era in the history of the solar system, and may have formed far beyond Jupiter's current orbit.
"Because the Trojans are remnants of the primordial material that formed the outer planets, they hold vital clues to deciphering the history of the solar system," said Harold F Levison, principal investigator of the Lucy mission from the Southwest Research Institute in Boulder, Colorado.
"Lucy, like the human fossil for which it is named, will revolutionise the understanding of our origins," said Levison.
The Psyche mission, targeted to launch in October of 2023, will explore one of the most intriguing targets in the main asteroid belt – a giant metal asteroid, known as 16 Psyche, about three times farther away from the sun than is the Earth.
This asteroid measures about 210 kilometres in diameter and, unlike most other asteroids that are rocky or icy bodies, is thought to be comprised mostly of metallic iron and nickel, similar to Earth's core.
Scientists wonder whether Psyche could be an exposed core of an early planet that could have been as large as Mars, but which lost its rocky outer layers due to a number of violent collisions billions of years ago.
The mission will help scientists understand how planets and other bodies separated into their layers – including cores, mantles and crusts – early in their histories.
"This is an opportunity to explore a new type of world – not one of rock or ice, but of metal," said Psyche Principal Investigator Lindy Elkins-Tanton of Arizona State University.
"16 Psyche is the only known object of its kind in the solar system, and this is the only way humans will ever visit a core. We learn about inner space by visiting outer space," said Elkins-Tanton.
Psyche, also a robotic mission, will be arriving at the asteroid in 2030, following an Earth gravity assist spacecraft manoeuvre in 2024 and a Mars flyby in 2025.